5,826 research outputs found
Double resonant absorption measurement of acetylene symmetric vibrational states probed with cavity ring down spectroscopy
A novel mid-infrared/near-infrared double resonant absorption setup for
studying infrared-inactive vibrational states is presented. A strong
vibrational transition in the mid-infrared region is excited using an idler
beam from a singly resonant continuous-wave optical parametric oscillator, to
populate an intermediate vibrational state. High output power of the optical
parametric oscillator and the strength of the mid-infrared transition result in
efficient population transfer to the intermediate state, which allows measuring
secondary transitions from this state with a high signal-to-noise ratio. A
secondary, near-infrared transition from the intermediate state is probed using
cavity ring down spectroscopy, which provides high sensitivity in this
wavelength region. Due to the narrow linewidths of the excitation sources, the
rovibrational lines of the secondary transition are measured with sub-Doppler
resolution. The setup is used to access a previously unreported symmetric
vibrational state of acetylene, in the
normal mode notation. Single-photon transitions to this state from the
vibrational ground state are forbidden. Ten lines of the newly measured state
are observed and fitted with the linear least-squares method to extract the
band parameters. The vibrational term value was measured to be at 9775.0018(45)
, the rotational parameter was 1.162222 ,
and the quartic centrifugal distortion parameter was 3.998(62), where the numbers in the parenthesis are one-standard
errors in the least significant digits
Quality of Life After Axillary or Groin Sentinel Lymph Node Biopsy, With or Without Completion Lymph Node Dissection, in Patients With Cutaneous Melanoma
The aim of this study was to asses quality of life (QoL) after axillary or inguinal sentinel lymph node biopsy (SLNB) with or without completion lymph node dissection (CLND) in patients with cutaneous melanoma by comparing patients to a norm group of the general population and by comparing QoL between four patient groups depending on surgical procedure and location, i.e., patients receiving an axillary or groin SLNB, or an axillary or groin CLND.Between 1995 and 2003, a total of 242 axillary and inguinal SLNBs were performed. Of the 127 patients eligible for the study, 116 patients participated (91%). QoL was measured by the 30-item European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30), the McGill Pain Questionnaire and the Groningen Activity Restriction Scale.Median age at diagnosis was 50 (range, 18-77) years; median Breslow thickness 2.0 (range, 1-13) mm; median follow-up 56 (range, 4-94) months. SLNB only was performed in 89 patients (77%): 48 in the groin and 41 in the axilla. CLND was performed in 27 patients (23%): 13 in the axilla and 14 in the groin. More postoperative complications (13 vs. 5; P <0.001) and lymphedema (10 vs. 8; P <0.001) occurred in the CLND group than in the SLNB group. The total group of patients reported better physical (P <0.001), role (P <0.001), emotional (P <0.001), and social functioning (P = 0.049), global QoL (P <0.001), and less fatigue (P <0.001) and pain (P <0.001) than a German norm group. Analysis of variance revealed significant differences in role functioning (P = 0.02) and tendencies toward physical problems (P = 0.051) and fatigue (P = 0.051) between the four groups. Post hoc Bonferroni tests showed that the axillary CLND group had more problems than the axillary and inguinal SLNB groups. Kruskal-Wallis tests showed that the axillary CLND group reported most pain.QoL in melanoma survivors after axillary or inguinal SLNB with or without CLND was better than that in a norm group. Patients who underwent CLND in the axilla after SLNB reported most problems.</p
The origin of peak-offsets in weak-lensing maps
Centroid positions of peaks identified in weak lensing mass maps often show
offsets with respect to other means of identifying halo centres, like position
of the brightest cluster galaxy or X-ray emission centroid. Here we study the
effect of projected large-scale structure (LSS), smoothing of mass maps, and
shape noise on the weak lensing peak positions. Additionally we compare the
offsets in mass maps to those found in parametric model fits. Using ray-tracing
simulations through the Millennium Run -body simulation, we find that
projected LSS does not alter the weak-lensing peak position within the limits
of our simulations' spatial resolution, which exceeds the typical resolution of
weak lensing maps. We conclude that projected LSS, although a major contaminant
for weak-lensing mass estimates, is not a source of confusion for identifying
halo centres. The typically reported offsets in the literature are caused by a
combination of shape noise and smoothing alone. This is true for centroid
positions derived both from mass maps and model fits.Comment: 6 pages, 4 figures, accepted for publication in MNRAS, significant
additions to v
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Genetic and environmental covariation between autistic traits and behavioral problems
Objective: To examine the overlap between autistic traits and other behavioral problems in a general population sample, and explore the extent to which this overlap is due to genetic or environmental factors. Method: Youth Self Report (YSR) data were collected in a general population sample of 424 twin pairs at 18 years of age, and their non twin siblings. In 197 of these twin families, self-report ratings on the Autism-spectrum Quotient (AQ) were collected. Results: Stepwise backward regression analyses revealed that of all 8 YSR syndrome scales, the Withdrawn Behavior (WB) and Social Problems (SOC) scale were the most important predictors of AQ scores, and together with sex, explained 23% of the variance in AQ scores. Genetic structural equation modeling showed that the overlap between AQ and WB and SOC was mainly due to genetic effects. About half of the genetic variance in AQ scores was specific to the AQ, with the remaining half shared with genetic variance in WB and SOC. Conclusions: Endorsement of autistic traits in a general population sample is associated with social and withdrawn behavioral problems and these problems partly share a common genetic etiology with autistic traits. However, most of the variance in AQ scores remains unexplained by YSR scores, and half of the genetic variance in AQ is unshared with WB and SOC. These results indicate that autistic traits have specific characteristics that are substantially genetically independent from other common but related behavioral domains such as social problems and withdrawn behavior
Methodological tests of the use of trace elements as tracers to assess root activity
peer-reviewedN.J.H. was funded by the Irish Research Council, co-funded by Marie Curie Actions under FP7. The field experiments A, B and G were supported by the European Community's Seventh Framework Programme (FP7/2007-2013) under the grant agreements FP7-266018 (AnimalChange) and FP7- 244983 (MultiSward). Experiment F was supported by the German Science Foundation (FOR 456).Background and aims
There is increasing interest in how resource utilisation in grassland ecosystems is affected by changes in plant diversity and abiotic conditions. Research to date has mainly focussed on aboveground responses and there is limited insight into belowground processes. The aim of this study was to test a number of assumptions for the valid use of the trace elements caesium, lithium, rubidium and strontium as tracers to assess the root activity of several grassland species.
Methods
We carried out a series of experiments addressing the reliability of soil labelling, injection density, incubation time, application rate and the comparability of different tracers in a multiple tracer method.
Results
The results indicate that it is possible to achieve a reliable labelling of soil depths. Tracer injection density affected the variability but not the mean level of plant tracer concentrations. Tracer application rates should be based on pilot studies, because of site- and species-specific responses. The trace elements did not meet prerequisites to be used in a multiple tracer method.
Conclusions
The use of trace elements as tracers is potentially a very useful tool to give insight into plant root activity at different soil depths. This work highlights some of the main benefits and pitfalls of the method and provides specific recommendations to assist the design of tracer experiments and interpretation of the results.N.J.H. was funded by the Irish Research Council, co-funded by Marie Curie Actions under FP7. The field experiments A, B and G were supported by the European Community's Seventh Framework Programme (FP7/2007-2013) under the grant agreements FP7-266018 (AnimalChange) and FP7- 244983 (MultiSward). Experiment F was supported by the German Science Foundation (FOR 456).European Unio
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